The houses on this stretch of West Grand Boulevard paint a picture of Detroit’s abandonment: timber rots and paint peels on a row of spacious family homes. One porch is obliterated by a 15-foot tree whose trunk has grown immediately outside the front door. No 2648, however, is as well preserved as when it was bought back in the late 1950s.

The sign outside still announces that this is Hitsville, USA and the basement steps still lead down to Studio A, the birthplace and former nerve centre of Motown Records. It is 60 years since the company’s founder, Berry Gordy, began his musical empire, a record label whose inimitable sound conquered the stark racial divides of 60s and 70s America.

Jamerson recorded the bass for What’s Goin’ On lying on his back after Gaye had found him in a bar, too drunk to sit up

The museum is currently fundraising for a planned $50m expansion and celebrities visit frequently – Michelle Obama made a surprise visit in December. But what’s most notable about Hitsville is its modesty. The room where the Supremes, the Temptations, and Martha Reeves and the Vandellas cut their first records is literally a converted garage.

The grand piano Stevie Wonder used to play is here, as well as the drums Marvin Gaye was originally hired to play. In the corner, on a stand, is a guitar. It belongs to Dennis Coffey, a 78-year-old who still rocks his wah-wah licks once a week in a midtown bar. Unlike Diana, Stevie and Marvin, Dennis doesn’t appear in Motown: The Musical. But he played on at least 100 million-selling records for the company, and there was a year when he was on three of the Top 10 and 10 of the Top 100 singles on the Billboardchart every month.

When Coffey first stepped into this place as a 28-year-old session musician, he knew he had just landed the biggest break of his life. “Playing for Motown was one of the best gigs in the country,” he remembers. “But it was a closed shop. They had a guard sitting on the front door at Hitsville, they didn’t want passersby trying their luck. You couldn’t break into the Funk Brothers unless you were asked.”

The Funk Brothers were the band that played on every one of Motown’s Detroit-era records. They were local jazz and blues players assembled by Gordy and whose skills he jealously guarded. Gordy wanted musicians who could help him create a new sound that would challenge the white monolith of rock’n’roll. “Berry was a visionary,” says Coffey. “He told me he could not have started Motown in any other city but Detroit because of the talent that was here.”

Coffey’s family had moved north to Michigan from Kentucky. He cut his first record aged 15, playing a guitar solo on Vic Gallon’s I’m Gone. Like Motown guitarist Eddie Willis, pianist Joe Hunter and drummer Pistol Allen, he was part of a wave of migrants from the south who were looking for work in the booming automotive city and brought their music with them. The musicianship rivalled anything from New York to New Orleans, and the result was a jazz and blues scene informed by rock’n’roll – a blend that defined the Motown sound. “The writers, arrangers and producers came up with the songs, but you couldn’t write that feeling we had on paper,” says Coffey. “Everything was built on our foundation.”

By the time Coffey joined the Funk Brothers, the band had propelled Motown to hundreds of No 1 hits, from My Girl and Tracks of My Tears to Dancing in the Street. Gordy knew how integral the Funk Brothers were to his success and banned them from playing for any other record companies. Coffey owed his place to his innovative use of the wah-wah pedal, which piqued the interest of producer Norman Whitfield, who was looking for ways to incorporate the emerging psychedelic aesthetic into Motown’s music. Two weeks later, Coffey had immortalised the sound with his guitar solo on the Temptations’ Cloud Nine. From then on, he was a key cog in the hit machine.

From 10am to 6pm every weekday – with union-stipulated breaks – Coffey and his fellow Funk Brothers sat along the walls of Studio A making musical history. “Our job was to do one song an hour and make them hits,” Coffey says. “All the musicians were playing at the same time, reading off the same master chart – and we’d record straight to tape, no amplifiers. So if you made a mistake or hit a bad chord they had to stop the tape. But we didn’t make mistakes at Motown. That was not part of the culture.”

Lead and backing vocals were recorded in separate sessions, after the band had laid down the track – the artists propelled to fame by these records were rare sightings. “I remember Marvin coming in for one session and smoking a joint the entire time. And Gladys Knight was in there once, trying to produce.” Trying? “Well, she had a little bit of attitude about it. She only tried that once.” A very young Michael Jackson visited with his dad Joe, who wanted to know what pedals Coffey was using.

Playing together six hours a day, five days a week meant the band weren’t just tight rhythmically, they were as close as family. “There was nobody with an ego problem, no fighting each other for parts. I don’t think that existed anywhere else.” Its three white members also made the band unusually racially diverse. When the Funk Brothers emerged from a session on the evening of 23 July 1967, they found the streets engulfed in violence and rioting. The black musicians shepherded their white counterparts to safety.

Of the dozen regulars, Van Dyke was the band’s father figure, the only man capable of reining in some of the others’ more unruly habits. Eddie “Bongo” Brown was the joker who could do pitch-perfect imitations of everyone else in the room and whose music stand was usually adorned with a girlie mag (he couldn’t read the notes anyway). The genius in the room, everyone agreed, was James Jamerson, whose funky one-fingered bass playing became the standard for a new generation.

Jamerson was Coffey’s musical mentor and close ally. He was also the wildest of the Funk Brothers – he recorded the bass part to What’s Goin’ On lying on his back after Marvin Gaye had tracked him down in a bar and found him too drunk to sit up. A bottle of Metaxa, a brand of Greek spirit, resided permanently in his instrument case, although Coffey claims Jamerson never let anyone see him drinking it on the job. “I tasted it once – phwoah! It was like moonshine.”

Coffey’s favourite Jamerson story is of the time he managed to foil a mugger with a pen. “We used to have these Italian fountain pens that could fire .22 calibre bullets,” he says. “Well when this guy pulled on him in the street and demanded his money, he got the pen behind his ear and said ‘No, give me your money!’ I met him in the bar that night and we sat there, drinking off this guy’s money.”

Motown’s move to Los Angeles in 1972 – as Gordy sought to expand his entertainment empire without his Detroit musicians – brought an abrupt end to the Funk Brothers. Most searched for gigs as the doors closed at smaller studios and publishing houses that had supported the Motown behemoth. “Their lives just fell apart,” says Coffey, who managed to score a hit of his own with Scorpio and followed the work out to California. He was soon playing sessions at the new Mowest studios: “But that was the end of the Motown sound. Berry had hit artists, sure, but it wasn’t the same.”

Coffey returned to Detroit and found a “factory rat” job on the assembly line at Ford. He retrained as a technical writer, gaining the bachelor’s and master’s degrees that hang proudly on his walls next to his gold record for Scorpio. But his friend Jamerson, who had also moved to LA, struggled to find work and sank into alcoholism. It killed him by the age of 47.

Coffey says he feels no bitterness about the way Motown used its studio musicians. “Berry builta corporation as you’d build any other corporation,” he says, “that’s just how he ran it.” There are just two other Funk Brothers still alive, and Coffey is the only one still performing. He’s excited by the regeneration of Detroit. “We have musicians who want to play, bar owners who want to put on the music and audience who want to pay for it.”

You can still catch him, every Tuesday night, at the Northern Lights Lounge. He’s the one in the black cap and black polo neck, playing to a relentless beat with an ease that completely belies his age. He’s the one bringing the funk.

• This story was amended on 23 April 2019 to correct the name of West Grand Boulevard.